Exposure to ultraviolet rays from the sun would affect the regulation of the endocrine system, responsible for the release of sex hormones in men.
- Exposure to radiation through the skin is the cause of the observed hormonal, physiological and behavioral changes.
- UVB rays increase testosterone levels.
The sun is the ally of amorous passion. Researchers at Tel Aviv University have found that exposure to ultraviolet rays from the sun affects the regulation of the endocrine system responsible for the release of sex hormones in humans. They published their results on August 24 in the journal Cell Reports.
A mechanism to better understand
It is known that ultraviolet rays from sunlight increase testosterone levels in men and that sunlight plays a major role in behavioral and hormonal regulation of sexuality. However, the mechanism responsible for this regulation remained unknown. The study provided a better understanding of this mechanism.
The exposure of the skin to radiation in question
For this, the researchers exposed mice to UVB, solar rays at wavelengths of 320 to 400 nanometers. The effect was dramatic as the females’ hormone levels increased significantly, enlarging their ovaries and prolonging their mating season, the attraction between males and females increased and both sexes were more willing to have sexual relations.
In a second experiment, the researchers repeated the same process, this time removing from the skin a protein called p53 which acts as a protection against its undesirable effects. It identifies DNA damage and activates pigmentation upon sun exposure. After exposing the mice to UVB, the researchers found no change in their sexual behavior.
The results led the researchers to believe that radiation exposure through the skin is the cause of the observed hormonal, physiological and behavioral changes. They add that the protection system is also responsible for regulating sexuality.
The sun increases testosterone
To confirm their findings in humans, the study authors had 32 volunteers complete questionnaires about romantic passion behaviors. The latter then renewed the exercise after being exposed to UVB in medical centers. They then showed an increase in romantic passion, and the men also noted an increase in levels of aggression.
The researchers note that similar results were found when they asked subjects to avoid sunlight for two days and then tan for about 25 minutes. Blood tests revealed that sun exposure resulted in a higher release of hormones like testosterone compared to a day before exposure. Data from the Israeli health services reported an increase in testosterone in men during the summer.
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